Switching means



Dec. 29, 1959 M. T. ROUDEBUSH ETAL 2,919,331

SWITCHING MEANS Filed Aug. 1, 1958 INVENTORS MELVIN 1'. ROUDEBUSH WILMERL. MOYER M Q wmyy Tl-LElR ATTORNEYS United States Patent SWITCHING MEANSMelvin T. Roudebush and Wilmer L. Mayer, Dayton,

Ohio, assignor's to The National Cash Register Company, Dayton, Ohio, acorporation of Maryland Application August 1, 1958, Serial No. 752,614

7 Claims. (Cl. 200-153) This invention relates to improvements inswitching means and more particularly to switches operating underhigh-speed conditions.

Previous switches of the prior art, when operating at high rates ofspeed, exhibited an inability to maintain a satisfactory consistentengagement of contacts which would meet the requirements for high-speedswitch operation. At this high rate of cyclic operation, the switchblade structure, on which the contacts were mounted, became subject tosecondary vibrations, thereby producing a stuttering effect on theoperation of the contacts. Accordingly, there is a need for a switchwhich will operate efficiently regardless of the speed of operation.

An object of this invention, therefore, is to provide an electric switchconstruction which will operate efficiently under very high-speedconditions.

Another object of this invention is to provide a highspeed switchcapable of maintaining a consistent contact engagement for long periodsof operation.

A further object of this invention is to provide a switch with controlmeans to insure eificient switching operation over a wide range ofspeeds.

With these and incidental objects in view, the invention includescertain novel features of construction and combinations of parts, apreferred form or embodiment of which is hereinafter described withreference to the drawing which accompanies and forms a part of thisspecification.

In the drawing:

Fig. l is a longitudinal sectional view through the assembled switch,showing the position of the cam and the contacts at the moment ofclosing.

Fig. 2 is a perspective View of the embodiment of this invention,showing the contacts in an open position.

Referring now to the drawing, there is shown in Fig. l a box-like switchsupport comprising a base 1, a front wall 2, a rear wall 3, side walls4, and a top wall 5. This support may be constructed of any suitableinsulating material. Rotatably supported in the side walls 4 are torsionbars 6 and 7, extending longitudinally between said side walls in aspaced and parallel relationship. The function of the torsion bars is toprovide resilient elements for the control. and storage of torsionalenergy.

'Rigidly secured to the torsion bars 6 and 7, by means of pins 8, areswitch arms 10 and 9, respectively. As shown in Fig. 2, both of theseswitch arms are positioned on the torsion bars in the same plane forcoaction with each other.

The outer stem 11 of each of the switch arms is cut down to provide arecessed surface 12, which is parallel to the inner faces 13 of theswitch arms.

Located immediately below the stems 11 and on the inner faces 13 of theswitch arms 9 and 10 are electrical contacts 14. The contacts may beconstructed of any suitable material which will provide a long contactlife under high-speed operating conditions.

Also rigidly secured to the torsion bars 6 and 7, by means of pins 8,are torsion arms 15 and 16, respectively. As shown in Fig. 2, thetorsion arm 15 is positioned on the torsion bar 6 so as to extend abovethe torsion bar, while the other torsion arm, 16, extends below thetorsion bar 7. Cooperating with the free end ice of each of the torsionarms 15 and 16 are a pair of adjusting screws 17 and 18, respectively,each of said adjusting screws being rotatably supported in the rear wall3, and secured in position by locknuts' 19, as shown in Fig. 1. As bestseen in Fig. 1, the head of each of the adjusting screws 17 and 1 8abuts the outer surface 20 of one of the torsion arms. It can be seenthat any pressure on the surfaces 20 of the torsion arms 15 and 16 bythe heads of the adjusting screws 17 and 18 will result incounter-clockwise rotation of the torsion bars 6 and 7, and willconsequently vary the pressure exerted by the contacts 14 on each other.

incorporation of the switch into an electrical circuit is accomplishedbythe use of terminals 36 secured to the adjusting screws 17 and 18through the use of locknuts 21. Connected to the terminals 51) are wires22' for conducting a current to and from the electrical contacts 14- bymeans of the adjusting screws 17 and 13, the torsion arms 15 and 16, thetorsion bars 6 and 7, and the switch arms 9 and 10.

Rotatably supported in the side walls 4 and spaced in parallelrelationship with the torsion bars 6 and 7 is an operating shaft 23powered by a motor (not shown). Rigidly secured to said shaft is acircular cam plate 24, the outer peripheral surface of which is linedwith a suitable insulating material 25. As may be seen in Fig. 1, thecam plate is mounted eccentrically on the shaft 23 and is positioned(Fig. 2) on said shaft so as to engage the outer surface 26 of theswitch arm 9 for movement of said arm.

Located in the rear wall 3 and rotatably supported thereby is anadjusting screw 27, the head 28 of which abuts the inner recessed face12 of the switch arm 10;

as shown in Fig. 1. Lateral movement of the adjusting screw biasesthe'switch arm 10 to vary the initial air gap between the switch arms 9and 10, and thus adjust the timing.

In the operation of the switch, the gap between the contacts 14,located, respectively, on the switch arms 9 and 10, is adusted byrotation of the adjusting screw 27. This gap controls the length of timethe contacts are together during a single revolution of the cam 24.After the air gap has been properly adjusted, the arms 15 and 16 arerotated in a counter-clockwise direction by the adjusting screws 17, 18.This rotation of the arms 15 and 16 applies a counter-clockwise twistingmoment to the torsion bars 6 and 7. Since the switch arms 9 and 16 arerigidly secured to the torsion bars, this counterclockwise momentrotates both the torsion bars and the switch arms in a counter-clockwisedirection. The magnitude of this initial moment applied to the torsionbars 6 and 7 varies directly with the operational speed of the switch.

Counter-clockwise rotation of the switch arm 9 biases said arm againstthe outer surface of the cam 24, while the same rotation biases theswitch arm 11 against the head of the adjusting screw '27. In homeposition of the switch, the shortest radius of the cam24 is between theshaft 23 and the switch arm 9, and the contacts 14 on the arms 9 and 10are spaced apart in open position. During the first half-cycle ofrotation of the cam 24, the switch arm 9 is displaced by the cam in aclockwise direction about the torsion bar 7. This movement results inthe contact 14 on the switch arm 9 coming into contact with the contact14 on the switch arm 10, thereby closing the contacts 14 and displacingthe arm 10 about the torsion bar 6 in a clockwise direction. Thisrotation of the arms 9 and 10' about the longitudinal axis of theirrespective torsion bars produces a clockwise twisting moment on thetorsion bars. Due to the already-existing moment on the torsion barsapplied by the arms 15 and 16, this clockwise moment applied by theswitch arms to --2,919,3a1 fir the torsion bar will be absorbed, and anytendency for the switch arms to be subjected to secondary vibration orfor the contacts to chatter will be eliminated. This will allow theswitch to be operated at very high speeds and still produce a cleanmaking and breaking of the contacts.

Of the second half-cycle of the cam revolution, the cam surfacedisplacing the switch arm 9 in a clockwise direction will be removedsufiiciently to allow said switch arm to be rotated in acounter-clockwise direction under the influence of the moment applied tothe torsion bar by the arms 15, 16. This counter-clockwise rotation ofthe switch arm will open the contacts 14 as the cam 24 returns to homeposition, and will thus break the circuit.

While the form of the mechanism herein shown and described is admirablyadapted to fulfill the objects primarily stated, it is not intended toconfine the invention to the form or embodiment herein disclosed, for itis susceptible of embodiment in various forms, all coming within thescope of the appended claims.

What is claimed is:

l. A switching device comprising, in combination, stationary mountingmeans; a pair of resilient members supported on the mounting means;contact supporting means secured to each of the resilient membersincluding a first contact supporting means and a second contactsupporting means; contact means mounted on each of said contactsupporting means; means for biasing said first contact supporting meanstoward the second contact supporting means for engagement of the contactmeans; an arm mounted on each of said resilient members; and means foradjustably limiting the movement of said arms, wherein opposing twistingmoments are exerted on each of said resilient members, the opposingmoments resulting from the movement of the arms and the contactsupporting means in directions opposite to each other.

2. A switching device comprising, in combination, stationary mountingmeans; a pair of resilient members supported on the mounting means;elongated supporting means having one end of each means secured to oneof said resilient members and comprising a first support means and asecond support means; contact means mounted on the free end of each ofsaid support means; means for biasing said first support means towardsthe second support means for engagement of the contact means; an armmounted on each of said resilient members; and means for adjustablylimiting the movement of said arms, wherein opposing twisting momentsare exerted on each of said resilient members, the opposing momentsresulting from the movement of the arms and the contact supporting meansin directions opposite to each other.

3. A switching device comprising, in combination, stationary mountingmeans; a pair of torsion bars supported on said mounting means in aspaced and parallel relationship; elongated support means having one endof each means secured to one of said torsion bars and comprising a firstsupport means and a second support means; contact means mounted on thefree end of each of said support means; means for biasing said firstsupport means towards said second support means for engagement of thecontact means; an arm mounted on each of said torsion bars; and meansfor adjustably limiting the movement of said arms, wherein opposingtwisting moments are exerted on each of said torsion bars, the opposingmoments resulting from the movement of the arms and the contactsupporting means in directions opposite to each other.

4. A switch comprising, in combination, stationary mounting means; apair of to'rsion bars rotatably supported on the mounting means ina-spaced and parallel relationship; means comprising a first elongatedswitch arm and a second elongated switch arm, each arm having one endrigidly mounted to one of said torsion bars; contact means mounted onthe free ends of said switch 4 7 arms; means for biasing the firstswitch arm towards the second switch arm for engagement of the contactson said arms; an arm mounted on each of said torsion bars; and means foradjustably limiting the movement of said arms, wherein opposing twistingmo'ments are exerted on each of said torsion bars, the opposing momentsresulting from the movement of the arms and the contact supporting meansin directions opposite to each other.

5. A switch comprising, in combination, insulated mounting means; a pairof torsion bars rotatably sup ported on the mounting means in a spacedand parallel relationship; a pair of switch arms, each having an endrigidly mounted to one of said torsion bars; a pair of contacts, due ofwhich is mounted on the free end of each of said switch arms; meansincluding an insulated cam, rotatably supported on said mounting means,for biasing one of said switch arms towards the other of said switch armfor engagement of the contacts on said arm; an arm mounted on each ofsaid torsion bars; and means for adjustably limiting the movement ofsaid arms, where in opposing twisting moments are exerted on each ofsaid torsion bars, the opposing moments resulting from the movement ofthe arms and the contact supporting means in directions opposite to eachother.

6. A switching device comprising stationary mounting means; a pair ofresilient members supported on the mounting means; means including afirst switch arm rigidly secured to one of said resilient means and asecond switch arm rigidly secured to the other of said resilient means;contact means mounted on each of said switch arms; means for biasingsaid first switch arm towards the second switch arm for engagement ofthe contact means on said arms; a first arm rigidly mounted on one ofsaid resilient members and a second arm rigidly mounted on the other ofsaid resilient members and a pair of adjusting screws threadedlysupported on the mounting means, said adjusting screw abutting saidfirst and second arms for adjustably limiting the movement of said arms,wherein opposing twisting moments are exerted on each of said resilientmembers, the opposing moments resulting from the movement of the armsand the switch arms in directions opposite to each other.

7. A switching device comprising insulated, mounting means; a pair oftorsion bars rotatably supported on said mounting means in a spaced andparallel relationship; a first switch arm having one end rigidly securedat right angles to one of said torsion bars; a second switch arm havingone end rigidly secured at right angles to the other of said torsionbars; means rotatably supported on said mounting means and located inabutting relationship with said second switch arm, thereby preventingrelative movement of said arm in one direction; a pair of electricalcontacts, each one of which is supported on the free end of said switcharms; an actuating means comprising a rotatable shaft carrying aninsulated rotary cam and supported on said mounting means, said cambeing in operative relation with said first switch arm such that uponrotation of said cam the first switch arm is displaced towards saidsecond switch arm for engage: ment therewith; a third arm having one endrigidly secured at right angles to one of said torsion bars; a fourtharm having one end rigidly secured at right angles to the other of saidtorsion bars; and a pair of adjusting screws threadedly supported onsaid mounting means and abutting said third and fourth arms foradjustably limiting the movement of said arms, wherein opposing twistingmoments are exerted on each of said torsion bars, the opposing momentsresulting from the movement of the third and fourth arms in a directionOpposite to that of the movement of the first and second switch arms.

References Cited in the file of this patent UNITED STATES PATENTS2,284,437 Lake May 26, 1942

